Enphase getting into storage systems...

[inetdog]

You mean Flea Bay isn't reputable?

Well, traditionally "reputable" means having a good reputation (and deserving it.)

[NeilTheCop]

You mean Flea Bay isn't reputable?

[inetdog]

What, yet another start-up led by a professor with a groundbreaking idea?

When I can buy a 20 KWH Ambri battery pack off E-Bay, then I'll be interested

When I can buy it from a reputable dealer rather than Flea-Bay or Kickstarter I will be even more interested.

[NeilTheCop]

Or maybe Ambri (www.ambri.com) will make their liquid battery happen and make it work. Who knows?

What, yet another start-up led by a professor with a groundbreaking idea?

When I can buy a 20 KWH Ambri battery pack off E-Bay, then I'll be interested

[JCP]

I think I read that Li-on batteries cost about $300 a Kwh. Cars only use 2/3 of the battery capacity to keep them going longer. So, a house would probably require a good 30KWh battery to be helpful (and that only covers a day of consumption or so). Today's cost: $9000. Maybe $3-4000 in a few years if all goes well.

Or maybe Ambri (www.ambri.com) will make their liquid battery happen and make it work. Who knows?

[kwilcox]

The Enphase system is unique in that it interfaces with third party home management systems like TED and Nest to control the exact amount of energy provided by PV based systems. Then it meters this energy such that net output to the grid is always zero. No other system that I know of can do this. No other system that I know of can optimize charging when power is flowing backward through the battery inverters either.

So I disagree with your statement that the tech has been around for a long time. I don't have empirical data to cite against your "cost effectiveness has not and is a long way out" statement however. I guess we'll have to wait until Enphase releases pricing for that.

[russ]

Well, Enphase certainly hasn't released pricing yet, but the tech is there.

The tech has been there for a long time - cost effectiveness has not and is a long way out.

[kwilcox]

Well, Enphase certainly hasn't released pricing yet, but the tech is there.

[paulcheung]

I don't know what AC coupling really means. I think these grid tied systems are missing a HUGE point. Any gt system should be able to make power during the day when the grid is down. It doesn't need to be elegant or perfect And it should be a feature for little extra cost. Its mostly an engineering cost to the company as most of the needed parts are already there. The inverter is already 90% done. Batteries are a PITA. A ridiculously expensive, wearing out when you need them useless when you don't PITA. I think most usual solar buyers would like some power from their system in an emergency if it was just a little more cost and took no maintenance. Almost nobody wants it if it doubles or even triples the price and cost another 50% every 10 years after that.

It won't happen until someone come up the solution for cost effective storage. the biggest problem is the cost of storage, you need it to stable the power and backup when the source is not be able to provide the power.

[russ]

...and not cost any more than without those features?

An old boss of mine had a comment for when we were discussing engineering and someone in the meeting said "I wish" or "I hope"

Something like, "Wish in one hand and crap in the other. Come back and tell us which hand fills up first".

[inetdog]

You would also like your Chevy to have all the features and speed of a Ferrari?

...and not cost any more than without those features?

[russ]

I don't know what AC coupling really means. I think these grid tied systems are missing a HUGE point. Any gt system should be able to make power during the day when the grid is down.

You would also like your Chevy to have all the features and speed of a Ferrari?

[nomadh]

I don't know what AC coupling really means. I think these grid tied systems are missing a HUGE point. Any gt system should be able to make power during the day when the grid is down. It doesn't need to be elegant or perfect And it should be a feature for little extra cost. Its mostly an engineering cost to the company as most of the needed parts are already there. The inverter is already 90% done. Batteries are a PITA. A ridiculously expensive, wearing out when you need them useless when you don't PITA. I think most usual solar buyers would like some power from their system in an emergency if it was just a little more cost and took no maintenance. Almost nobody wants it if it doubles or even triples the price and cost another 50% every 10 years after that.
So I still don't really feel I have an answer to "Is the enphase going to allow off grid solar?" Does ac coupling imply that? It still looks to me enphase only cares about shifting the time it can supply power while on grid. Maybe this new battery pack can be hot rodded? Sort of like how the prius was hot rodded to allow charging from home until Toyota introduced like they were marketing geniuses. Once again I was thinking what stupid company didn't include such an obvious, inexpensive feature like this to begin with.

[paulcheung]

Nope. AC coupling allows GT arrays to power off-grid/battery based PV systems. The SE Conext is a good example of this. Here's how they do it:

http://solar.schneider-electric.com/wp-content/uploads/2014/04/Conext-XW-AC-Coupling-Application-Note_Rev-B.pdf

Conext actually varies the line frequency to cycle the GT array on/off when the batteries reach full charge.

Here's the Enphase whitepaper on how to do AC coupling with their GT inverters (this forms the basis of their battery system too btw):

http://enphase.com/global/files/Enph...ed-Systems.pdf

First sentence from above link: "AC Coupling allows use of Enphase Microinverters with off-grid and battery-based photovoltaic systems.".

This is why their storage system is pretty much genius. The batteries form an integral part of the panel/inverter system. The new Envoy S controller controls charge by cycling the inverters using their established powerline control protocol (used today for Enlighten based monitoring/control). End result: deliver just enough energy to minimize the home's grid power requirements. In short, its designed to avoid the need to use the grid as a battery.

The key here is the existing Enphase powerline control protocol which allows the Envoy S to precisely control M2xx GT inverters and their new bi-directional S275 inverters used by the battery system. All this running on Enphase Engage cable. Genius.

Here's some examples based on my current understanding of the system which will be available in 3Q15:

I could, for example, set this system (PV Array/Enphase GT microinverters/Enphase batteries/Envoy S controller) up with a single demand side outlet that is my garage 40 Amp car charger outlet. No POCO interconnect anywhere. If I plug enough batteries into the trunk cable, I can store an entire days worth of power locally then just release it when the car is on the charger.

Or, instead of a 40Amp outlet, I could connect the demand side to my main panel, then tie in my TED5000 which is one of the supported Envoy S interconnect components (along with NEST thermostats and a whole bunch of other exciting products). Now it has instantaneous whole house usage available for charging calculations. Excess array production would then be diverted to local storage and be "played back" when array production was insufficient to meet the home's instantaneous demand. Net metering hassles avoided. "demand vs. usage" debate still rages though.

Or, to avoid the "demand vs. usage" debate, I set up a new load center on the system demand side that isn't connected to the POCO. Now I run kitchen/bathroom circuits there. TED5000 (or other) monitors this load center for charging optimization.

The result: partial grid defection and not a single thing the utility can do about it. ...This is also a complete off-grid system minus generator backup btw. There might be a supported generator solution too but I didn't see it.

Sadly, it is the utilities themselves that are driving this innovation by refusing to embrace their potentially lucrative role as an energy storage provider. The last connectivity example above will be my reply to a 2015 rate-case rubber stamp in SE WI.

Again, this is my current understanding of the system which was just announced. If anybody has corrections (like a possible grid-tie requirement which isn't clear at this point) then I'd love to hear it.

edit:

It appears that S series inverters will be required at the panels too. M2xx inverters cannot be controlled by an Envoy S. Bummer.

Whole of these points are come back to storage, If you can find any form of storage cost effective, by all mean you will be able to go off grid and won't have to worry anything about the grid down.

With the off grid without generator, the generator's purpose is to keep the battery alive while you have rain or snow for days. if you have other mean to do that, by all means.

The bottom line is cost effective storage when the sun is not shinning on your panels..

[kwilcox]

Nope. AC coupling allows GT arrays to power off-grid/battery based PV systems. The SE Conext is a good example of this. Here's how they do it:

http://solar.schneider-electric.com/wp-content/uploads/2014/04/Conext-XW-AC-Coupling-Application-Note_Rev-B.pdf

Conext actually varies the line frequency to cycle the GT array on/off when the batteries reach full charge.

Here's the Enphase whitepaper on how to do AC coupling with their GT inverters (this forms the basis of their battery system too btw):

http://enphase.com/global/files/Enph...ed-Systems.pdf

First sentence from above link: "AC Coupling allows use of Enphase Microinverters with off-grid and battery-based photovoltaic systems.".

This is why their storage system is pretty much genius. The batteries form an integral part of the panel/inverter system. The new Envoy S controller controls charge by cycling the inverters using their established powerline control protocol (used today for Enlighten based monitoring/control). End result: deliver just enough energy to minimize the home's grid power requirements. In short, its designed to avoid the need to use the grid as a battery.

The key here is the existing Enphase powerline control protocol which allows the Envoy S to precisely control M2xx GT inverters and their new bi-directional S275 inverters used by the battery system. All this running on Enphase Engage cable. Genius.

Here's some examples based on my current understanding of the system which will be available in 3Q15:

I could, for example, set this system (PV Array/Enphase GT microinverters/Enphase batteries/Envoy S controller) up with a single demand side outlet that is my garage 40 Amp car charger outlet. No POCO interconnect anywhere. If I plug enough batteries into the trunk cable, I can store an entire days worth of power locally then just release it when the car is on the charger.

Or, instead of a 40Amp outlet, I could connect the demand side to my main panel, then tie in my TED5000 which is one of the supported Envoy S interconnect components (along with NEST thermostats and a whole bunch of other exciting products). Now it has instantaneous whole house usage available for charging calculations. Excess array production would then be diverted to local storage and be "played back" when array production was insufficient to meet the home's instantaneous demand. Net metering hassles avoided. "demand vs. usage" debate still rages though.

Or, to avoid the "demand vs. usage" debate, I set up a new load center on the system demand side that isn't connected to the POCO. Now I run kitchen/bathroom circuits there. TED5000 (or other) monitors this load center for charging optimization.

The result: partial grid defection and not a single thing the utility can do about it. ...This is also a complete off-grid system minus generator backup btw. There might be a supported generator solution too but I didn't see it.

Sadly, it is the utilities themselves that are driving this innovation by refusing to embrace their potentially lucrative role as an energy storage provider. The last connectivity example above will be my reply to a 2015 rate-case rubber stamp in SE WI.

Again, this is my current understanding of the system which was just announced. If anybody has corrections (like a possible grid-tie requirement which isn't clear at this point) then I'd love to hear it.

edit:

It appears that S series inverters will be required at the panels too. M2xx inverters cannot be controlled by an Envoy S. Bummer.